support class native clause

pkg/compiler/lib/src/parser/element_listener.dart

Index: pkg/compiler/lib/src/parser/element_listener.dart
diff --git a/pkg/compiler/lib/src/parser/element_listener.dart b/pkg/compiler/lib/src/parser/element_listener.dart
index 964d1dba7fb912c45d0e0e3afe7bdc8ad945fa67..0366a37503b83cc822a441a1b0a77efc1377befb 100644
--- a/pkg/compiler/lib/src/parser/element_listener.dart
+++ b/pkg/compiler/lib/src/parser/element_listener.dart
@@ -278,6 +278,13 @@ class ElementListener extends Listener {
     }
   }
 
+  @override
+  void handleNativeClause(Token nativeToken, bool hasName) {
+    if (hasName) {
+      popNode(); // Pop the native clause which in this case is a StringLiteral.
+    }
+  }
+
   @override
   void endClassDeclaration(
       int interfacesCount,
@@ -285,6 +292,7 @@ class ElementListener extends Listener {
       Token classKeyword,
       Token extendsKeyword,
       Token implementsKeyword,
+      Token nativeToken,
       Token endToken) {
     makeNodeList(interfacesCount, implementsKeyword, null, ","); // interfaces
     popNode(); // superType